Washington is re-imposing strict sanctions on Iran, which were lifted under the 2015 deal to curb the country's nuclear ambitions.

Danish oil product shipping operator Maersk Tankers said it would wind down its customer agreements in Iran by November, while German insurer Allianz said on Tuesday it was preparing to wind down Iran-related business.

Italy's Eni, which last June signed a provisional agreement with Tehran to conduct oil and gas feasibility studies, said after Washington's decision to quit the nuclear deal last week that it had no plans for new projects in Iran.

A withdrawal from the Iran project would not affect Total's current overall production targets as the group had since opened up other growth opportunities, it said.

SP11 is the biggest proposed project between an worldwide oil company and Iran and if Total withdraws, it will likely deal a significant blow to Tehran.

He explained that the French company will not be fined for pulling out of the contract, but added that Total's expenditure on the contract will not be paid back until completion of the project.

The EU's top energy official, Commissioner Miguel Arias Canete, is heading to Iran for talks from May 18 to 21 to discuss ways of trying to overcome renewed US sanctions against Iran's oil industry. Joe Kaesar, the CEO of Germany's Siemens, told CNN his company would not be able to do any new business with Tehran.

In a statement, Total said it "will have to unwind all related operations" before November 4, unless it's granted a specific waiver by USA authorities that would protect it against sanctions.

"The issue is that Iranian transactions can't be processed though any part of the banking system that needs access to the USA dollar", Gammel said. The company has a few options if they leave. "We have a situation where there is a will to impose sanctions on Europeans and a resentment towards European companies who are now being accused of supporting a terrorist state. The EU can't compel or really protect the private sector", Sanam Vakil, associate fellow at Chatham House said of Total's announcement.

The Phase 11 contract will automatically go to Total's consortium partner China National Petroleum Corporation (CNPC) and local player Petropars if the French player does pull out, Iranian officials have previously said.